McGinn sustained a fractured left ankle in Villa's dismal 3-1 home defeat to Southampton on December 21, with Smith claiming then the Scotland midfielder would likely be on the sidelines for three months.
With the 27-year-old not due to return until mid-March at the earliest, it means he would miss the Wembley showdown with Manchester City on March 1, and make him touch and go for Scotland's Euro 2020 play-off date with Israel at Hampden on March 26.
With those targets in McGinn's mind, especially the league cup final, Smith would not be surprised to see him available to take on Pep Guardiola's side.
"He has been doing a lot of work in the pool and is due to come out of the protective boot," said Smith. "Once that happens we can start advancing his recovery.
"I have not got a time limit, but knowing John he would probably have pencilled in the cup final. Knowing the medical staff they will have rubbed that out.
"He is a fighter and a quick healer. I would not rule it out (playing in the final). He has a big date with the Euros as well. He will be itching to get back, that is for sure."
While being fit for the final might serve as an incentive for McGinn, Smith has warned the rest of his squad not to use it as a carrot for raising their game over the next three Premier League matches prior to what will be the club's ninth league cup final.
With survival paramount, Villa face a crucial relegation clash at Bournemouth on Saturday, followed by a home date with Tottenham and a further trip to the south coast to take on Southampton before facing City.
"To be honest, each game should be a carrot to the players," insisted Smith.
"We are in the Premier League and every game is big. We face Bournemouth, Tottenham and Southampton, and then Manchester City in the cup final.
"Each game is big enough for them to be a carrot for the players who want to get into the team."